ClickHouse/src/IO/ZstdDeflatingWriteBuffer.h
2020-11-17 19:02:10 +03:00

39 lines
1.0 KiB
C++

#pragma once
#include <IO/BufferWithOwnMemory.h>
#include <IO/CompressionMethod.h>
#include <IO/WriteBuffer.h>
#include <zstd.h>
namespace DB
{
/// Performs compression using zlib library and writes compressed data to out_ WriteBuffer.
class ZstdDeflatingWriteBuffer : public BufferWithOwnMemory<WriteBuffer>
{
public:
ZstdDeflatingWriteBuffer(
std::unique_ptr<WriteBuffer> out_,
int compression_level,
size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
char * existing_memory = nullptr,
size_t alignment = 0);
/// Flush all pending data and write zlib footer to the underlying buffer.
/// After the first call to this function, subsequent calls will have no effect and
/// an attempt to write to this buffer will result in exception.
void finish();
~ZstdDeflatingWriteBuffer() override;
private:
void nextImpl() override;
std::unique_ptr<WriteBuffer> out;
ZSTD_CCtx * cctx;
ZSTD_inBuffer input;
ZSTD_outBuffer output;
bool flushed = false;
};
}